Viruses present in gastrointestnal illnesses have not been carefully evaluated. The objective of this program is the development of techniques for the cultivation to high titer of viruses isolated from the ileum of patients with Crohn's disease and from the colon of patients with ulcerative colitis. Although these viruses may or may not be etiologically related to inflammatory bowel diseases, their presence requires thorough evaluation. They have been cultivated in titers too low to expect sufficient in vivo replication to produce disease and satisfy Koch's postulates. In order to properly characterize the viruses recently cultivated from patients with these illnesses, techniques must be developed to grow these agents to titers sufficently high to enable the development of standard cross neutralization and other serologic assays. To accomplish those objectives, we propose to evaluate several tissue culture systems including primary human ileum and colon cultures, human diploid lung cells, primary monkey kidney cells, human embryonic kidney and primary human amnion cultures as well as Vero monkey kidney cultures and human fetal intestinal cultures. If these culture systems fail to support the growth of virus to titers greater than 10 to the minus 5th power, co-cultivation, feeder layer cultures and cell fusion studies will be undertaken. To aid in the assessment of cultivated viruses, hyperimmune guinea pig antibody prepared against tissue culture grown viruses with appropriate control materials will be prepared and specific neutralization tests will be undertaken. These studies are an essential step in the evaluation of the viruses cultivated from patients with inflammmatory bowel diseases. If successful, they will lead to the proper characterization of the viruses and eventually to a definition of their role, if any, in human disease.